2 Ultrasonic Sensors

Ultrasonic transceivers are able to convert an electrical signal to an ultrasonic burst and receive the resulting reflected wave when directed at a barrier. Several property comparisons can be made between the transmitted and received bursts in order to determine different factors. For example, the time between transmitting a burst and receiving the reflected wave, termed "time of flight", can be used to determine distance, or if the distance is known, a material can be uniquely identified by calculating its sound attenuation coefficient. If directed at a moving object, the Doppler shift (frequency alteration due to velocity) between the transmitted and received bursts can be measured and used to determine speed. Other deductions are possible. However, these summarize the most common.